Rotary gas meter with flange connection

ABSTRACT

A gas meter with a rated maximum flow capacity of greater than 3,000 CFH (Cubic Feet per Hour)—for example, between 3,500 CFH and 7,000 CFH—is provided with 2-inch flange connectors. One or more undercuts are provided in the meter body to promote satisfactory performance in terms of, for example, differential pressures at the meter inlet and outlet.

CROSS-REFERENCE

This application is a continuation of U.S. application Ser. No.16/150,720 filed Oct. 3, 2018, the entire contents of which areincorporated herein by reference, which claims to U.S. ProvisionalPatent Application No. 62/570,718 filed Oct. 11, 2017, the entirecontents of which are incorporated herein by reference.

FIELD

This disclosure relates generally to gas meter equipment, and morespecifically to rotary gas meters with flange connections.

INTRODUCTION

Gas meters may be used to measure volumes of gas transported and/or usedfor heating or cooling purposes. For large-scale and/or industrial uses,most gases are typically sold on a price-per-volume basis (e.g. $5 per1,000 cubic feet). Accordingly, it is generally considered desirable tomeasure gases being transported and/or used with a relatively highdegree of accuracy.

A common method of providing accurate measurement of atransported/consumed gas is the use of one or more positive displacementrotary gas meters. When gas flows through such a rotary gas meter, fixedvolumes of gas are displaced by, for example, two figure-eight impellersthat rotate in opposite directions within a cylinder of known volume.The impellers of the gas meter rotate because of a lower differentialpressure at the outlet of the meter than is present at the inlet. Asthey rotate, a fixed volume of gas or other fluid is entrapped and thenmoved toward the outlet. Therefore, with each full rotation of theimpellers, a known volume of gas or other fluid is displaced through theoutlet.

SUMMARY

The following introduction is provided to introduce the reader to themore detailed discussion to follow. The introduction is not intended tolimit or define any claimed or as yet unclaimed invention. One or moreinventions may reside in any combination or sub-combination of theelements or process steps disclosed in any part of this documentincluding its claims and figures.

Gas meters, such as rotary gas meters, typically have a rated flowcapacity, which can be expressed in CFH (Cubic Feet per Hour). Ratedflow capacity is often a (if not the) significant consideration whenselecting a gas meter (or gas meters) for use in a particularapplication. For example, a designer of a gas piping system may select agas meter rated for 80% of the expected maximum gas flow through thesystem.

Also, gas meters, such as rotary gas meters, are often provided withconnection interfaces that conform to one or more industry standards.For example, the B16.5 Standard (as published by the American Society ofMechanical Engineers (ASME) and/or the American National StandardsInstitute (ANSI)) covers pressure-temperature ratings, materials,dimensions, tolerances, marking, testing, and methods of designatingopenings for pipe flanges and flanged fittings.

The size of the inlet and outlet ports of a gas meter is typicallyproportional to the rated flow capacity of the gas meter. That is, gasmeters with larger rated flow capacities typically have larger inlet andoutlet ports. For example, for rotary gas meters with flange connectionsat their inlet and outlet ports, gas meters with flow ratings of lessthan 3,000 CFH (and in some cases those rated for 3,000 CFH) aretypically provided with 2-inch flange connections, while gas meters withflow ratings of between 3,000 to 7,000 CFH are typically provided with3-inch flange connections. Larger meters (e.g. greater than 7,000 CFH)typically have larger flange connections (e.g. 4-inch or 6-inch orlarger).

In some markets, demand for gas consumption (e.g. in industrial and/orcommercial sectors) is increasing, in some cases drastically.Consequently, there is expected to be a demand to increase gasthroughput in existing gas flow systems. However, once a gas flow systemhas been installed in e.g. an industrial, commercial, or residentialbuilding, increasing the rated flow capacity of the system may present anumber of challenges.

For example, a gas flow system initially designed for a flow capacity of3,000 CFH (or less) may have used 2-inch ANSI pipes and flanges. In theconventional standard, a gas flow system for a higher flow capacity(e.g. 3,500 or 5,000 or 7,000 CFH) would use 3-inch ANSI pipes andflanges. Accordingly, converting an existing 3,000 CFH rated system thathas 2-inch pipe and flange connectors to increase the system capacity toe.g. 5,000 CFH would typically require redesigning and reconstructingthe piping system (e.g. cutting out existing 2-inch flange connectorpipe fittings and re-welding new 3-inch pipe fittings), which mayincrease the cost of increasing the system flow capacity. Also,reconstructing a piping system also requires shutting off the flow ofgas (at least temporarily) during the reconstruction, which is oftenconsidered undesirable.

In accordance with one aspect of this disclosure, a rotary gas meterhaving a rated capacity of greater than 3,000 CFH (e.g. 3,500 or 5,000or 7,000 CFH) is provided with standard 2-inch flange connectors,preferably conforming to the ANSI/ASME 16.5 Standard (e.g. 2-inch Class125/150 ANSI B16.5 flange connections).

Providing a gas meter with standard 2-inch flange connectors and a ratedmaximum flow capacity of greater than 3,000 CFH may have one or moreadvantages. For example, such a gas meter may be used to replace anexisting gas meter that has standard 2-inch flange connectors and amaximum flow rating of 3,000 CFH (or less) without requiring redesign orreconstruction of the existing 2-inch piping system. Put another way,since the new gas meter (with a larger flow rating) has 2-inch ANSIflange configurations at the meter's inlet and outlet, the new, largermeter can be coupled to an existing 2-inch piping system withoutexpanding and/or replacing the pipes and/or flange connections in theexisting (2-inch) system, which would typically otherwise be required toinstall a larger gas meter that has conventional flange connectionsizing (i.e. 3-inch ANSI). This may save time and/or decrease costs whenincreasing the rated capacity of an existing gas flow system.

In accordance with a broad aspect, there is provided a rotary gas metercomprising: a meter body having a gas inlet port and an associated inletflange connection, a gas outlet port and an associated outlet flangeconnection, and a main chamber in flow communication with the gas inletport and the gas outlet port; wherein at least one undercut is providedin the meter body between the gas inlet port and the main chamber;wherein at least one undercut is provided in the meter body between themain chamber and the gas outlet port; wherein the inlet flangeconnection is a standard 2-inch connection; wherein the outlet flangeconnection is a standard 2-inch connection; and wherein the rotary gasmeter has a rated maximum flow capacity of greater than 3,000 CFH (CubicFeet per Hour).

In some embodiments, the rated maximum flow capacity is between 3,500CFH and 7,000 CFH.

In some embodiments, the rated maximum flow capacity is about 5,000 CFH.

In some embodiments, the inlet flange connection conforms to theANSI/ASME 16.5 Standard.

In some embodiments, the outlet flange connection conforms to theANSI/ASME 16.5 Standard.

In some embodiments, the at least one undercut provided in the meterbody between the gas inlet port and the main chamber is at an angle ofbetween about 30 degrees and about 60 degrees to the gas inlet port.

In some embodiments, the at least one undercut provided in the meterbody between the gas inlet port and the main chamber is at an angle ofabout 45 degrees to the gas inlet port.

In some embodiments, the at least one undercut provided in the meterbody between the main chamber and the gas outlet port is at an angle ofbetween about 30 degrees and about 60 degrees to the gas outlet port.

In some embodiments, the at least one undercut provided in the meterbody between the main chamber and the gas outlet port is at an angle ofabout 45 degrees to the gas outlet port.

In some embodiments, the rotary gas meter further comprises a positivedisplacement metering apparatus comprising lobed impellers positioned inthe main chamber.

It will be appreciated by a person skilled in the art that a method orapparatus disclosed herein may embody any one or more of the featurescontained herein and that the features may be used in any particularcombination or sub-combination.

These and other aspects and features of various embodiments will bedescribed in greater detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the described embodiments and to show moreclearly how they may be carried into effect, reference will now be made,by way of example, to the accompanying drawings in which:

FIG. 1 is a perspective view of a gas meter having a rated flow capacityof 2,000 CFH (Cubic Feet per Hour) and a 2-inch flange connection;

FIG. 2 is a cross-sectional view of the body of the gas meter of FIG. 1,taken along line 2-2;

FIG. 3 is a cross-sectional view of the body of the gas meter of FIG. 1,taken along line 3-3;

FIG. 4 is a top view of the body of the gas meter of FIG. 1;

FIG. 5 is a perspective view of a gas meter having a rated flow capacityof 5,000 CFH and a 3-inch flange connection;

FIG. 6 is a cross-sectional view of the body of the gas meter of FIG. 5,taken along line 6-6;

FIG. 7 is a cross-sectional view of the body of the gas meter of FIG. 5,taken along line 7-7;

FIG. 8 is a top view of the body of the gas meter of FIG. 5;

FIG. 9 is a perspective view of a gas meter having a rated flow capacityof 5,000 CFH and a 2-inch flange connection;

FIG. 10 is a cross-sectional view of the body of the gas meter of FIG.9, taken along line 10-10;

FIG. 11 is a cross-sectional view of the body of the gas meter of FIG.9, taken along line 11-11;

FIG. 12 is a top view of the body of the gas meter of FIG. 9;

FIG. 13 is top perspective view of the body of the gas meter of FIG. 9;and

FIG. 14 is a plot of test results of differential pressures for a 5,000CFH gas meter having a 3-inch flange connection, and for a 5,000 CFH gasmeter having a 2-inch flange connection.

The drawings included herewith are for illustrating various examples ofarticles, methods, and apparatuses of the teaching of the presentspecification and are not intended to limit the scope of what is taughtin any way.

DESCRIPTION OF EXAMPLE EMBODIMENTS

Various apparatuses, methods and compositions are described below toprovide an example of an embodiment of each claimed invention. Noembodiment described below limits any claimed invention and any claimedinvention may cover apparatuses and methods that differ from thosedescribed below. The claimed inventions are not limited to apparatuses,methods and compositions having all of the features of any oneapparatus, method or composition described below or to features commonto multiple or all of the apparatuses, methods or compositions describedbelow. It is possible that an apparatus, method or composition describedbelow is not an embodiment of any claimed invention. Any inventiondisclosed in an apparatus, method or composition described below that isnot claimed in this document may be the subject matter of anotherprotective instrument, for example, a continuing patent application, andthe applicant(s), inventor(s) and/or owner(s) do not intend to abandon,disclaim, or dedicate to the public any such invention by its disclosurein this document.

Furthermore, it will be appreciated that for simplicity and clarity ofillustration, where considered appropriate, reference numerals may berepeated among the figures to indicate corresponding or analogouselements. In addition, numerous specific details are set forth in orderto provide a thorough understanding of the example embodiments describedherein. However, it will be understood by those of ordinary skill in theart that the example embodiments described herein may be practicedwithout these specific details. In other instances, well-known methods,procedures, and components have not been described in detail so as notto obscure the example embodiments described herein. Also, thedescription is not to be considered as limiting the scope of the exampleembodiments described herein.

While the apparatus and methods disclosed herein are describedspecifically in relation to conventional positive displacement rotarygas meters, it will be appreciated that the apparatus and methods mayalternatively be used with other types of rotary gas meters.

As discussed above, the size of the inlet and outlet ports of a gasmeter, such as a rotary gas meter, is typically proportional to therated flow capacity of the gas meter. Conventionally, rotary gas meterswith flow ratings of less than 3,000 CFH (and in some cases those ratedfor 3,000 CFH) are typically provided with standard 2-inch flangeconnections (e.g. conforming to the ANSI/ASME 16.5 Standard, such as2-inch Class 125/150 ANSI B16.5 flange connections). Rotary gas meterswith flow ratings of between 3,000 to 7,000 CFH are typically providedwith 3-inch flange connections (e.g. 3-inch ANSI connectors).

FIGS. 1 to 4 illustrate an example of a positive displacement rotary gasmeter 1000 having a rated flow capacity (or simply ‘rating’) of 2,000CFH. The gas meter 1000 includes a meter body 1100, which has a gas flowinlet 1110 provided at an upper end of the meter body 1100, and a gasflow outlet 1120 provided at a lower end of the meter body 1100.

In the illustrated example, standard 2-inch flange connections 1130 areprovided at the gas flow inlet 1110 and outlet 1120 of meter body 1100.For example, 2-inch flange connections 1130 may conform to the ANSI/ASME16.5 Standard (e.g. 2-inch Class 125/150 ANSI B16.5 flange connections).

In use, a gas flow to be measured (e.g. natural gas) enters the meterbody via gas flow inlet 1110, passes through an internal inletantechamber or throat 1115 and into a main chamber 1150. After passingthrough the main chamber 1150, the gas flow passes through an internaloutlet antechamber or throat 1125 and exits the meter body via gas flowoutlet 1120.

Any suitable metering equipment may be provided in main chamber 1150 tomeasure the gas flow. For example, as the gas flow passes through themain chamber 1150, one or more impellers (not shown) positioned in themain chamber 1150 may rotate in proportion to the gas flow. For example,in a positive displacement rotary gas meter, with each full impellerrotation a known volume of gas travels between gas flow inlet 1110 andgas flow outlet 1120.

An inlet instrumentation port 1117 in communication with inletantechamber or throat 1115 provides access for one or more sensors (e.g.a pressure sensor or a temperature sensor) to measure conditionsassociated with the gas flow entering the meter body 1100. Similarly, anoutlet instrumentation port 1127 in communication with outletantechamber or throat 1125 provides access for one or more sensors tomeasure conditions associated with the gas flow exiting the meter body1110.

FIGS. 5 to 8 illustrate an example of a positive displacement rotary gasmeter 2000 having a rated flow capacity (or simply ‘rating’) of 5,000CFH. Elements having similar structure and/or performing similarfunction as those in the example gas meter illustrated in FIGS. 1 to 4are numbered similarly, with the reference numerals incremented by 1000.

In the illustrated example, standard 3-inch flange connections 2130 areprovided at the gas flow inlet 2110 and outlet 2120 of meter body 2100.For example, 3-inch flange connections 2130 may conform to the ANSI/ASME16.5 Standard (e.g. 3-inch Class 125/150 ANSI B16.5 flange connections).

FIGS. 9 to 13 illustrate an example of a positive displacement rotarygas meter 3000 having a rated flow capacity (or simply ‘rating’) of5,000 CFH. Elements having similar structure and/or performing similarfunction as those in the example gas meter illustrated in FIGS. 1 to 4are numbered similarly, with the reference numerals incremented by 2000.

In the illustrated example, standard 2-inch flange connections 3130 areprovided at the gas flow inlet 3110 and outlet 3120 of meter body 3100.For example, 2-inch flange connections 3130 may conform to the ANSI/ASME16.5 Standard (e.g. 2-inch Class 125/150 ANSI B16.5 flange connections).

As discussed above, providing a gas meter with standard 2-inch flangeconnectors and a rated maximum flow capacity of greater than 3,000 CFH(e.g. between 3,500 CFH and 7,000 CFH), such as the example illustratedin FIGS. 9 to 13, may have one or more advantages when compared to gasmeters with conventional flange connection sizes (i.e. 3-inch flangeconnections for gas meters with flow ratings of between 3,000 to 7,000CFH). However, modifying the design of a gas meter having a maximumrated capacity of between 3,000 CFH to 7,000 CFH to have a standard2-inch flange connection (e.g. a 2-inch ANSI flange connection) whilemaintain an acceptable level of metering accuracy presented one or morechallenges.

For example, one significant challenge was the increase in pressure atthe gas flow inlet 3110 and gas flow outlet 3120 that resulted fromdecreasing their diameters from the diameter specified for a standard3-inch ANSI flange connection (i.e. 3.00 inches) to the diameterspecified for a standard 2-inch ANSI flange connection (i.e. 1.56inches).

As shown in FIGS. 9 to 11 and 13, a first pair of undercuts 3160 areprovided in the meter body 3100 at an upper portion of the antechamberor throat 3115 of the gas flow inlet 3110. Undercuts 3160 provide anincreased flow area between gas flow inlet 3110 and main chamber 3150,which is thought to provide expansion conditions similar to thoseprovided by a diffuser. Accordingly, providing undercuts 3160 in meterbody 3100 may provide improved expansion conditions of an inlet gasflow, which may assist in reducing differential pressure between the gasflow inlet 3110 and the gas flow outlet 3120.

Also, a second pair of undercuts 3160 are provided in the meter body3100 at a lower portion of the antechamber or throat 3125 of the gasflow outlet 3120. These undercuts provide an increased flow area betweenmain chamber 3150 and gas flow outlet 3120, which is thought to providecompression conditions similar to those provided by a nozzle.Accordingly, providing undercuts 3160 in meter body 3100 may provideimproved compression conditions of an outlet gas flow, which may assistin improving the performance of the meter in terms of differentialpressure between the gas flow inlet 3110 and the gas flow outlet 3120.

For example, test results for a 5,000 CFH rated gas meter with a 2-inchflange connection (e.g. as illustrated in FIGS. 9 to 13) are comparedwith results for a 5,000 CFH rated gas meter with a 3-inch flangeconnection (e.g. as illustrated in FIGS. 5 to 8) in table 1, and theresults are plotted in FIG. 14.

TABLE 1 Percentage Differential of Max Flow Pressure Flow [%] [CFH][inH₂0] 5,000 CFH, 3-inch 97.41% 4870.64 1.04 flange connection 19.80%990.22 0.10 5,000 CFH, 2-inch 93.52% 4675.80 1.02 flange connection22.32% 1115.95 0.10

These results indicate that a 5,000 CFH rated gas meter with a 2-inchflange connection and undercuts 3160 as illustrated in FIGS. 9 to 13 maybe expected to provide comparable metering performance when compared toa 5,000 CFH rated gas meter with a 3-inch flange connection (e.g. asillustrated in FIGS. 5 to 8).

In the example illustrated in FIGS. 9 to 13, two undercuts 3160 areprovided in the meter body 3100 between gas flow inlet 3110 and mainchamber 3150, and two undercuts 3160 are provided in the meter body 3100between main chamber 3150 and gas flow outlet 3120. While this isconsidered a preferable configuration, e.g. in terms of symmetry and/ormachinability, it will be appreciated that more or fewer undercuts couldbe provided in alternative embodiments.

Also, in the illustrated example each undercut 3160 is oriented at anangle 3165 of about 45° (see e.g. FIG. 11). It will be appreciated thatangle 3165 may be greater or smaller (e.g. from about 30° to about 60°),depending on e.g. the dimensions and/or CFH rating of meter body 3110.

Also, in the illustrated example each undercut 3160 has a generallyparabolic profile. It will be appreciated that in alternativeembodiments undercuts 3160 may have circular or other suitable profiles.

Providing a gas meter with standard 2-inch flange connectors and a ratedmaximum flow capacity of greater than 3,000 CFH (e.g. a meter asillustrated in FIGS. 9 to 13) may have one or more advantages. Forexample, such a gas meter may be used to replace an existing gas meterthat has standard 2-inch flange connectors and a maximum flow rating of3,000 CFH or less (e.g. a meter as illustrated in FIGS. 1 to 4) withoutrequiring redesign or reconstruction of the existing 2-inch pipingsystem.

Put another way, since the new gas meter—with a larger flow rating—hasstandard 2-inch flange connections at the meter's inlet and outlet, thenew, larger meter (e.g. a meter as illustrated in FIGS. 9 to 13) can becoupled to an existing 2-inch piping system without expanding and/orreplacing the pipes and/or flange connections in the existing (2-inch)system, which would typically otherwise be required to install a largergas meter that has conventional flange connection sizing (e.g. a meterwith 3-inch flange connections, e.g. a meter as illustrated in FIGS. 5to 8). This may save time and/or decrease costs when increasing therated capacity of an existing gas flow system. For example, this mayreduce or avoid time required: to redesign a piping system; toreconfigure a piping system to accommodate a 3-inch flange connection;to leak-test a piping system after installation of the new meter; and/orto shut down and/or ventilate a piping system (e.g. to drain existinggas from a piping system prior to installing new piping and/or flangeconnections).

As used herein, the wording “and/or” is intended to represent aninclusive-or. That is, “X and/or Y” is intended to mean X or Y or both,for example. As a further example, “X, Y, and/or Z” is intended to meanX or Y or Z or any combination thereof.

While the above description describes features of example embodiments,it will be appreciated that some features and/or functions of thedescribed embodiments are susceptible to modification without departingfrom the spirit and principles of operation of the describedembodiments. For example, the various characteristics which aredescribed by means of the represented embodiments or examples may beselectively combined with each other. Accordingly, what has beendescribed above is intended to be illustrative of the claimed conceptand non-limiting. It will be understood by persons skilled in the artthat other variants and modifications may be made without departing fromthe scope of the invention as defined in the claims appended hereto. Thescope of the claims should not be limited by the preferred embodimentsand examples, but should be given the broadest interpretation consistentwith the description as a whole.

1. A method to replace a first rotary gas flow meter having a first flowrating in cubic feet per hour, the first rotary gas flow meter havingrespective ports to connect to inlet and outlet flange connections thathave a diameter associated with the first flow rating, the methodcomprising: providing a second rotary gas flow meter for directconnection to the inlet and outlet flange connections in place of thefirst rotary gas flow meter, the second rotary gas flow metercomprising: a meter body having a main chamber, an inlet port incommunication with the main chamber via an inlet antechamber, anopposing outlet port in communication with the main chamber via anoutlet antechamber, and wherein: the inlet port and the opposing outletport connect respectively with the inlet and outlet flange connectionswithout resizing or adapting the diameter; and each of the inletantechamber and outlet antechamber having at least one undercut toprovide increased flow area through the meter body, the second rotarygas flow meter having a second flow rating that exceeds the first flowrating.
 2. The method of claim 1, wherein the first flow rating is lessthan or equal to 3000 CFH, and the second flow rating is greater than3000 CFH.
 3. The method of claim 1, wherein the diameter is 2 inches. 4.The method of claim 1, wherein the diameter is 3 inches.
 5. The methodof claim 1, wherein at least one of the inlet and outlet flangeconnections conforms to the ANSI/ASME 16.5 Standard.
 6. The method ofclaim 1, wherein the at least one undercut in each antechamber is a pairof opposed undercuts.
 7. The method of claim 6, wherein the pairs ofundercuts are substantially symmetrical.
 8. The method of claim 1,wherein each undercut is oriented at an angle of between 30 to 60degrees to its respective inlet port and outlet port.
 9. The method ofclaim 1, wherein each undercut has a parabolic profile.
 10. The methodof claim 1, wherein the second rotary gas flow meter has aninstrumentation port connecting to at least one of the inlet antechamberand the outlet antechamber, and the method further comprises connectinginstrumentation through the instrumentation port.
 11. The method ofclaim 10, wherein the instrumentation is a pressure sensor.
 12. Themethod of claim 10, wherein the instrumentation is a temperature sensor.13. The method of claim 1, further comprising connecting: the inlet portto the inlet flange connection; and the opposing outlet port to theoutlet flange connection; without resizing or adapting the diameter. 14.A rotary gas flow meter system, comprising: a rotary gas flow meterhaving a flow rating in cubic feet per hour, the meter comprising: ameter body having a main chamber; an inlet port in communication withthe main chamber via an inlet antechamber; an opposed outlet port incommunication with the main chamber via an outlet antechamber; and eachof the inlet antechamber and outlet antechamber having at least oneundercut to provide increased flow area through the meter body; and aninlet flange connection and an outlet flange connection for directlyconnecting with the inlet port and outlet port respectively, wherein theflange connections have a diameter smaller than a diameter associatedwith the flow rating.
 15. The meter system of claim 14, wherein the flowrating is greater than 3000 CFH.
 16. The meter system of claim 14,wherein at least one of the inlet and outlet flange connections conformsto the ANSI/ASME 16.5 Standard.
 17. The meter system of claim 14,wherein the at least one undercut in each antechamber is a pair ofopposed undercuts.
 18. The meter system of claim 17, wherein the pairsof undercuts are substantially symmetrical.
 19. The meter system ofclaim 14, wherein each undercut is oriented at an angle of between 30 to60 degrees to its respective inlet port and outlet port.
 20. The metersystem of claim 14, wherein each undercut has a parabolic profile. 21.The meter system of claim 14, wherein the second rotary gas flow meterhas an instrumentation port connecting to at least one of the inletantechamber and the outlet antechamber to receive instrumentationthrough the instrumentation port.